EP3204209B1 - Blown film extrusion head with inverter device and a purging method - Google Patents

Description

The present invention relates to a blow head having a turning device for turning a melt in a melt channel and a method for performing a rinsing process in a blow head.

It is known that extrusion devices are used to produce a plastic melt. This plastic melt can be used in many different ways. For example, it is conceivable to introduce the melt into a cavity of an injection molding device in order to produce corresponding components there by injection molding. It is also known that the melt is made available for a so-called blow extrusion process in which a blown film is extruded. In all In some cases, it is necessary that at the end of the extruder the liquefied melt is transported to the respective place of use via corresponding melt channels. These channels can be of any complexity and in particular can also be divided into individual channels.

A disadvantage of the known solutions of the extrusion devices is that they involve a high outlay for changing the material. A so-called rinsing process must be carried out if a material change from a first melt material to a second melt material is to take place. If, for example, a product with a blue film color is produced for a blown film extrusion device and then a change to a transparent film color is desired, the blue film color and the corresponding melt material must first be rinsed out of the individual melt channels. For this purpose, the extrusion device is already operated with the follow-up material until most of the old material of the melt has been rinsed out.

Since the transport speed for melt channels in the edge region of these melt channels is essentially zero, the old material adheres to it, so to speak, the rinsing process is very time-consuming. In the case of blow extrusion devices with a throughput of up to approx. 120 kg of melt per hour, a rinsing process can usually take 20 minutes. take up to 1.5 hours. For each film layer for which a material change is to take place, this therefore leads to 120 kg or more scrap material from the melt. If there are several layers of film, this amount is multiplied by the number of layers of film, even if only a single layer of film is rinsed. Reject rates of up to 1000 kg can be achieved with this. At the same time, the rinsing time is a dead time for the machine in which no usable production can take place. Accordingly, known extrusion devices are, for example, from the publications US2011 / 001267 A1 and CN101691061 B with the corresponding rinsing procedure with regard to the time required and with regard to the costs incurred as well as the material scrap with clearly recognizable disadvantages.

It is an object of the present invention to at least partially remedy the disadvantages described above. In particular, it is an object of the present invention to reduce the time for the rinsing process in a cost-effective and simple manner.

The above object is achieved by a blow head with the features of claim 1 and a method with the features of claim 10. Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are described in connection with the blow head according to the invention apply, of course, also in connection with the method according to the invention and vice versa, so that with respect to the disclosure of the individual aspects of the invention, reference can always be made to one another.

A turning device is used to turn a melt in a melt channel of the die head according to the invention. For this purpose, the turning device has a melt inlet and a melt outlet, at least one melt guiding means being arranged between the melt inlet and the melt outlet. The melt guiding agent serves to shift the melt from the middle of the melt inlet to the edge of the melt outlet. Furthermore, the melt guide means is designed for shifting melt from the edge of the melt inlet into the middle of the melt outlet.

The middle of the melt channel is basically to be understood as any region that is spaced from the edge. In particular, there is a shifting away from the edge. For example, the center of the melt outlet can be the entire melt outlet area at a distance of approximately 5 mm from the edge.

The turning device thus automatically rearranges the melt in the melt channel without any moving parts by means of active guidance using the melt guide means. The turning device can be inserted into the melt channel or form part of the melt channel. A fluid-communicating connection to the melt channel is established via the melt inlet, so that the melt can flow into the turning device via the melt inlet. After the When the melt has entered, the melt is layered over the melt guide in the manner according to the invention. At the melt outlet, the shifted melt will leave the turning device again and continue to flow via the fluid-communicating connection in the melt channel.

According to the invention, the melt guiding means are designed for shifting the melt. Two basic shift functionalities are made available. On the one hand, the melt from the center is used at the melt inlet and guided to the edge of the melt outlet. At the same time and over the same length, the melt is shifted from the edge of the melt inlet into the middle of the melt outlet. Thus, the material from the center at the melt inlet is exchanged with the material at the edge of the melt inlet, so that a completely shifted melt layer situation is present at the melt outlet.

The turning device now considerably reduces the flushing time when used in an extrusion device. Thus, in a rinsing situation in the extrusion device, it can be assumed that old melt material remains longer in the area of the edge of the melt channel than in the middle. Thus, the middle of the melt channel will be filled with completely fresh and thus new melt material relatively quickly during the rinsing process, while a high proportion of old material still adheres to the edge. By using the turning device, this old material is now shifted from the edge of the melt channel into the center of the melt channel and thus into the area of the rapid or higher flow rate. This means that, so to speak, old melt material in front of the turning device is shifted into the middle of the melt channel after the turning device, so that it can now be removed more quickly in the middle. The fact that this rearrangement takes place in the manner according to the invention enables a significant reduction in the rinsing time by faster removal of the old material from the melt channel.

In particular, the turning device can achieve a reduction of up to 50% of the total rinsing time. Another advantage is the reduction of the melt residence time at the edge even in normal operation. That way reduce the thermal influence on the material, thereby reducing or even avoiding material impairments.

The turning device can be inserted in the melt channel or form the melt channel. Of course, two or more turning devices with a defined distance can also be provided in a melt channel. It is preferred, as will be explained in more detail later, if the turning device is arranged in the center of the melt channel, essentially in relation to the length thereof.

The melt guidance with the aid of the melt guidance means can be designed in a wide variety of ways. The functions that will be explained later can thus be made available in a division by a melt guiding means just as is conceivable by active guide channels within the melt channel. These two different turning functions are explained in more detail below.

It can thus be advantageous if, in the turning device, the at least one melt guide means has a first guide channel with a guide opening in the middle of the melt inlet and at least one guide outlet at the edge of the melt outlet. An active turning takes place here within a single melt channel, so that an installation of a separate turning device into an existing geometry of a melt channel is also conceivable. By picking it up in the guide opening, the new or fresh material of the melt is now led to the edge and is output there via the guide exit at the melt exit. There it now displaces the old material located there in the middle, so that a complete shifting can be achieved by passive shifting. Of course, however, the old material can also be actively moved from the edge into the center, as is explained in more detail by a second guide channel in the following paragraph. A guide channel can be understood to mean a completely closed channel. However, laterally partially open guide channels in the form of so-called slides or ramps are to be understood as guide channels in the sense of the present invention. Accordingly, the guide opening and the guide exit can each have a completely bordered geometry or be provided with a side opening.

A further advantage can be if, in the turning device according to the preceding paragraph, the at least one melt guide means has a second guide channel with a guide outlet in the middle of the melt outlet and at least one guide opening at the edge of the melt inlet. The second guide channel thus serves, so to speak, for the reverse functionality as the first guide channel. The melt and thus old melt material can now be picked up from the edge at the melt inlet via the guide opening and actively guided with the second guide channel into the middle via the guide outlet at the melt outlet. The corresponding shifting according to the invention from the edge to the center and from the center to the edge is thus possible not only by displacing but also by actively guiding and shifting. The combination of two guide channels is preferably provided in parallel, so that the guide opening of the first guide channel and the guide opening of the second guide channel are arranged in the flow direction at the same or essentially the same location on the turning device. At the same time, it is advantageous if the guide outlet of the first guide channel and the guide outlet of the second guide channel are also arranged at the same or substantially the same position at the melt outlet with respect to the flow direction. It is also advantageous if all the guide channels of the at least one melt guiding means have the same or essentially the same free flow cross-section in order to be able to ensure a clean shifting, in particular with defined volume flows. The individual flow cross sections are preferably designed to be able to provide the same or substantially the same flow velocities. An undesirable tearing off of individual layers from one another is thus avoided with a high degree of probability and thus with great certainty.

It is also advantageous if, in the turning device, the at least one melt guiding means has a dividing section with a first partial channel and a second partial channel. In this case, a dividing section for dividing the melt into partial channels is arranged in front of the dividing section and a combination section for bringing the melt together from the partial channels is arranged after the dividing section. This version of a melt guide is of course, in principle, can be combined with the melt guide means of the two preceding paragraphs. This division function can also be used to rearrange. The quantity of melt is thus divided into the two subchannels via a distribution section. Of course, this also applies to the edge layer of the melt, so that in the two subchannels only part of the edge, in particular half of the edge, is provided with old material, while in the region of the division section the other half of the edge is already provided with fresh material . If the combination section for merging the melt from the subchannels is geometrically aligned in a corresponding manner, this means that at least part of the boundary layer is retained with new material even when the partial streams of the melt are combined. The functionality of dividing and combining can thus also ensure a possibility of a shifting according to the invention. In particular, such a partial rearrangement is combined with a corresponding division section with guide channels, as explained in the preceding paragraphs.

The turning device according to the preceding paragraph can be developed in such a way that the combination section is designed for a central bringing together of the edge sections of the melt. This means that there is an explicit geometric alignment of the individual subchannels in the combination section. If, for example, after the division section, the edge sections with old material of the melt are on the outside of the respective subchannel, then the two subchannels can be brought together in the combination section in such a way that the two edge sections of the melt are now brought together in the center of the subchannels with old material. The partial flows of the melt are thus recombined with a complete or essentially complete shifting, so that by skillfully recombining the partial flows the boundary layer in front of the melt inlet has shifted into the middle at the melt outlet. At the same time, new material was moved from the center of the melt outlet to the edge layers and thus to the edge at the melt outlet. The respective diameter of the subchannels is preferably adapted to the diameter before the dividing section and after the combination section.

According to the invention, the blow head has a displacement device for displacing the turning device between a first position and a second position. In the first position, the melt inlet and the melt outlet are in fluid-communicating connection with the melt channel. In the second position, the melt inlet and the melt outlet are separated from the melt channel. The displacement device can thus perform a movement of the turning device, for example in a translatory, rotary or combined manner. In particular, a tube piece or a channel piece is provided for the turning device in the second position, which connects the two remaining end sections of the melt channel in a fluid-communicating manner. The shifting device thus makes it possible, so to speak, to switch on the shifting function by pushing in the turning device and to switch it off by pushing out the turning device. Since the turning device generates a corresponding pressure loss situation due to its turning functionality, it is advantageous to switch off this turning function in normal operation. This means that the increased pressure loss is only used during the flushing process to ensure the appropriate shifting function. The increased pressure loss of the turning device is switched off by pushing the turning device into the second position in normal operation and accordingly can no longer interfere.

It can also be advantageous if, in the blow head according to the invention, the displacement device has a piece of melt channel with a length which corresponds or essentially corresponds to the distance between the melt inlet and the melt outlet. When moving from the first position to the second position, a melt channel piece can therefore be pushed to the position at which the turning device was previously arranged. In other words, the melt channel piece replaces the turning device in the rest of the melt channel and thereby completes it. This allows an essentially uninterrupted continuous melt channel to be made available for normal operation. For the flushing situation, the melt channel piece is then simply removed again from the fluid-communicating position in the melt channel via the displacement device and the turning device is pushed in its place. This can be done both manually and mechanically using the drive device described later. The advantage of this embodiment is that Combination in the single shifter. In particular, the melt channel piece and also the turning device and thus the melt inlet and the melt outlet are provided with parallel or substantially parallel channel axes.

A further advantage can be if, in the blow head according to the invention, the displacement device has a guide section for guiding the displacement movement between the first position and the second position. This can be understood as a backdrop guide or contracting sliding surfaces. From a technical point of view, other solutions are also conceivable for the management section. The direction of movement and the distance of movement for the displacement device and thus for the turning device is determined by the guide section or by a plurality of guide sections. Of course, the guide section can also have corresponding stops in order to exactly define the end positions for the first position and the second position. With regard to the direction of movement, a guide section can in particular provide a linear or essentially linear displacement movement. However, curved translational movements or even rotational movements are also conceivable in the sense of the present invention.

It is also advantageous if, in the blow head according to the invention, the displacement device is designed to move the turning device between the first position and the second position along a translation path, in particular along a straight line. A translation is particularly simple, compact and inexpensive to design, particularly with regard to executing a management functionality. The translation, in particular along a straight line, also allows a particularly short displacement distance and thus a quick switchover between the shifting function and the normal operating situation. If a drive device is provided for the displacement movement in the displacement device, then a movement along a translation path, in particular along a straight line, can take place without the interposition of a transmission. In particular, such a drive device is a linear drive, which is also inexpensive, space-saving and easy to use.

It can be a further advantage if, in the blow head according to the invention, the displacement device has a drive device, in particular in the form of an electric motor, for carrying out the displacement between the first position and the second position. This is, in particular, a reversible displacement option, so that the displacement process can be carried out essentially freely in both directions between the two positions. The drive device is designed in particular as a linear drive in order to be able to provide a translation path, in particular along a straight line, for the displacement device. The regulation of this drive device is preferably connected to the regulation of the blow head in order to be able to provide the exact pressure loss as information of the regulation of the blow head. When switching over to the washing situation, this information in the shifting device can automatically lead to the corresponding shifting movement.

It is also advantageous if in the blow head according to the invention the melt inlet and the melt outlet have a free flow cross section which corresponds to or essentially corresponds to the free flow cross section of the melt channel. In other words, a fluid-communicating connection between the melt inlet and the melt channel or between the melt outlet and the melt channel is possible in a stepless manner and without an edge or diameter variation. Such a turning device can be inserted completely into the melt channel or even partially form the melt channel. A free flow cross section is to be understood as the cross section perpendicular to the flow at the respective position. In other words, the free flow cross section forms the flow cross-sectional area over which the volume flow of the melt can flow.

It is also advantageous if, in the blow head according to the invention, the free flow cross section corresponds or essentially corresponds to the free flow cross section of the melt inlet and / or the free flow cross section of the melt outlet. In particular, this embodiment is combined with the embodiment according to the preceding paragraph. The flow cross section of the melt guiding means is preferably the sum all melt guiding agents. Through this correspondence, a constant free flow cross section is thus made available, so that the pressure loss due to narrowing of the cross section is avoided or essentially avoided. This significantly reduces the pressure loss that occurs when the melt flows through it. There remains exclusively or essentially exclusively a pressure loss, which is generated by the corresponding action on the flow direction and thus by the active layering of the melt. For example, widening of the melt channel can allow such a geometric correlation in the area of the turning device. It is also conceivable that a corresponding adjustment of the flow cross-sections is provided by the corresponding diameter of the sub-channels when dividing in a dividing section.

In particular, such a blow head with two or more melt channels is provided for different layers of the blown film. The turning device is preferably arranged in the same or identical configuration in all melt channels, in order to be able to provide the same flushing time reduction for all melt channels in the manner according to the invention.
A blow head according to the preceding paragraph can be developed in such a way that the turning device is arranged in the middle or essentially in the middle of the melt channel in relation to the length of the melt channel. This is an optimized positioning of the turning device, which allows the maximum reduction of the flushing time by approx. 50%. Of course, two or more turning devices are also possible, which are preferably used with the same or identical division in the respective melt channel.

In a blow head according to the invention, it can be advantageous if a displacement device with at least two turning devices is provided for a joint displacement of the two turning devices between a first position in which the first turning device is in fluid-communicating communication with the melt channel and a second position, in which the second turning device is in fluid-communicating communication with the melt channel. This allows a total of three different positions to be taken with the shifting device. In addition to the standard operating situation, in which a piece of melt channel preferably allows a corresponding completion of the melt channel, two positions with turning devices in use are now conceivable. The individual turning devices differ from one another with regard to their shifting functionality, so that a different pressure loss or a different geometric influence on the flow conditions in the respective turning device can be achieved specifically. Depending on the operating situation in the rinsing process and in particular also depending on the melt material actually used and its viscosity, a correspondingly adapted turning device can be selected. Of course, more than two turning devices can also be used in this way. This makes it possible to further improve the flushing performance via the adaptation and, in particular, to avoid undesired overloading of the pump device.

In the case of a blow head according to the invention, it is also conceivable that with a combination of two or more turning devices one behind the other, each turning device covers only a part of the respective edge and thus only shifts the melt into the middle from this part of the edge. Each turning device can preferably perform the shifting for a different circumferential section, so that after passing through all turning devices, melt has been shifted from the full circumference into the center. For example, four turning devices one behind the other can cover a 90 ° circumference of the edge with the re-layering function, so that in total the entire circumference of 360 ° is re-layered.

Another object of the present invention is a method for performing a flushing process in a blow head according to the present invention, comprising the method steps according to claim 10.

The method according to the invention has the same functionality according to the invention as the blow head according to the invention, so that the same advantages are also achieved.

The method according to the invention provides that the turning device is shifted into a fluid-communicating position with the melt channel before the rinsing process is carried out by means of the shifting device. In other words, the shifting functionality can now be switched on by performing the shifting movement within the shifting device before carrying out the flushing process. Switching between different pressure loss situations between the application situation and the flushing situation can thus be carried out inexpensively, simply and effectively.

It is also advantageous if, in a method according to the invention, the reversing device is moved into a position after performing the rinsing process by means of a shifting device, without a fluid-communicating connection to the melt channel. This is, so to speak, the switching off of the stratification function, so that in particular a melt channel piece instead of the turning device completes the melt channel. This also makes it possible to switch inexpensively and simply between the shifting functionality in the flushing situation and the normal situation when using the blow head.

Of course, a blow head according to the invention can also be used in other extrusion systems, for example in a film extrusion, in particular in a flat film extrusion. The blow head can thus basically be designed as an extrusion head.

Fig. 1

eine schematische Darstellung während eines Spülvorgangs bei bekannten Extrusionsvorrichtungen,

Fig. 2

die Situation gemäß Fig. 1 beim Einsatz einer Wendevorrichtung,

Fig. 3

eine Ausführungsform einer Wendevorrichtung,

Fig. 4

die Ausführungsform der Fig. 3 mit weiterer Darstellung von Strömungsverhältnissen der Schmelze,

Fig. 5

eine weitere Ausführungsform einer Wendevorrichtung,

Fig. 6

eine schematische Darstellung der Wirkung einer Wendevorrichtung,

Fig. 7

eine weitere Ausführungsform einer Wendevorrichtung,

Fig. 8

eine weitere Ausführungsform einer Wendevorrichtung,

Fig. 9

eine Ausführungsform eines erfindungsgemäßen Blaskopfs, und

Fig. 10

eine weitere Ausführungsform eines erfindungsgemäßen Blaskopfes.

Further advantages, features and details of the invention emerge from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. They show schematically:

Fig. 1

1 shows a schematic illustration during a rinsing process in known extrusion devices,

Fig. 2

the situation according Fig. 1 when using a turning device,

Fig. 3

one embodiment of a turning device,

Fig. 4

the embodiment of the Fig. 3 with further representation of flow conditions of the melt,

Fig. 5

another embodiment of a turning device,

Fig. 6

a schematic representation of the effect of a turning device,

Fig. 7

another embodiment of a turning device,

Fig. 8

another embodiment of a turning device,

Fig. 9

an embodiment of a blow head according to the invention, and

Fig. 10

a further embodiment of a blow head according to the invention.

In Fig. 1 shows a melt channel 110 with a flow direction from left to right, as it appears during the rinsing process. A free flow cross section 70 is provided within the melt channel 110, through which melt 200 flows. A distinction must be made here between old melt material 220 and new melt material 210. Here it can be clearly seen that a ramp-shaped or conical shape is formed between the old melt material 220 and the new melt material 210 over the elongated course of the melt channel 110 during the flushing process. This cone moves to the right during the rinsing time, until finally most of the old melt material 220 has been discharged and the active production can be continued.

In Fig. 2 the mode of operation of a turning device 10 is shown. Here, there is now a shifting from the edge of the melt 200 into the center of the melt 200 and vice versa. At the melt inlet 20 of the turning device 10, material is accordingly taken up from the edge of the melt 200 and made available in the middle at the melt outlet 30. Conversely, fresh or new melt material 210 is guided from the center at the melt inlet 20 to the edge of the melt outlet 30. As can be clearly seen, the resulting amount of old melt material 220 at the right end of the melt channel 110 is reduced Fig. 2 occurred at the same time during the rinsing process as for Fig. 1 .

The 3 and 4 show a first embodiment of the turning device 10. This turning device 10 is equipped with two guide channels 42 and 44 as the melt guide means 40. A guide opening 44a is provided at the edge 24 of the melt inlet 20 via a ring collector, which is not explained in detail, so that the corresponding melt 200 can flow into the second guide channel 44 there. This is with the arrows in Fig. 4 shown. The shifting from the edge into the center for this material of the melt 200 now takes place via a guide outlet 44b in the middle 32 of the melt outlet 30.

In the same way, a guide opening 42a of the first guide channel 42 is provided in the middle 22 of the melt inlet 20, which makes it possible along the arrows in FIG Fig. 3 to shift the melt 200 to the edge 34 of the melt outlet 30 and the corresponding guide outlet 42b. This is a technical solution by means of active layering, the turning device 10 being part of the melt channel 110.

The Fig. 5 shows reduced complexity with respect to the embodiments of FIG 3 and 4 . Only a closed second guide channel 40 with a corresponding guide opening 44a and guide exit 44b is provided here. The remaining material of the melt 200 is either passed unaffected from the melt inlet 20 through the melt guide means 40 at the upper end or is guided to the lower edge. The corresponding cuts AA and BB are in the lower area of the Fig. 5 shown, where the arrow lines also represent the corresponding shifting movement.

The 6 and 7 show the possibility to provide a reallocation by means of a division functionality. Starting from a melt channel 110 according to Fig. 7 the melt 200 will be divided into two subchannels 46a and 46b of the divided section 46 via a divided section 47. This leads to a distribution according to the Fig. 6 . While starting from the melt channel 110 completely surrounds the old melt material 220 with the new melt material 210, the division into the subchannels 46a and 46b will only cover about half of the circumference with the old melt material 220. The other half in the subchannels 46a and 46b is already provided with new melt material 210 on the edge. If the two subchannels 46 for the edge regions are brought together with the old melt material 220 by skillful combining, a complete or at least partial shifting can also be carried out using this division function.

The Fig. 8 schematically shows a possible further embodiment of a turning device 10 with this division functionality. This is divided into a total of four subchannels 46a and 46b and recombined in a combination section 48. The corresponding distribution is also schematic of old melt material 220 and new melt material 210 are shown in the corresponding channels. After combining or merging on the combination section 48, the edge sections with the old material 220 are located completely in the center, so that the surrounding edge in the melt channel 110 is essentially completely formed by the new melt material 210.

In Fig. 9 shows how a turning device 10 can be arranged in a melt channel 110 in a blow head 100. This can be any of the described embodiments of the turning device 10. The turning device 10 has a displacement device 60. According to the Fig. 9 the turning device 10 is in the second position, and thus apart from fluid-communicating engagement with the melt channel 110. This is the operating position. For the washing situation, the turning device 10 is introduced into the melt channel 110 via the displacement device 60 and can thus provide the functionality according to the invention for reducing the washing time. A drive device 64 is provided for the movement of the displacement, which here has an electric motor. The displacement takes place along a straight line and is guided by a guide section 62 of the displacement device 62. Furthermore, a melt channel piece 114 is provided in the displacement device 60, which in the second position according to the Fig. 9 completed the melt channel 110. The blow head of this embodiment is equipped with an annular blow outlet 112.

In the Fig. 10 is a variation of the embodiment of FIG Fig. 9 shown for a blow head 100. Here, the displacement device is equipped with two separate and, above all, different turning devices 10. The shifting device can now assume a total of three different positions. In addition to the operational function of Fig. 10 Two different rinsing positions can be adopted with the different turning devices 10, so that they can be adapted to different needs during the rinsing process.

Reference list

10th

Turning device

20

Melt entrance

22

Middle of the melt entrance

24th

Edge of the melt entrance

30th

Melt outlet

32

Middle of the melt outlet

34

Edge of the melt outlet

40

Melting agents

42

first guide channel

42a

Guide opening

42b

Lead exit

44

second guide channel

44a

Guide opening

44b

Lead exit

46

Division

46a

first subchannel

46b

second subchannel

47

Partitioning section

48

Combination section

60

Slider

62

Guide section

64

Drive device

70

free flow cross section

100

Blow head

110

Melt channel

112

Blow outlet

114

Melt channel piece

200

melt

210

New melt material

220

Old melt material

Claims (10)

1. A blow head (100) for the implementation of a blown film extrusion process, having at least one melt channel (110) for conveying the molten material (200) to a blow outlet (120) of the blow head, wherein in at least one melt channel (110) at least one overturning device (10) for overturning a molten material (200) is arranged in a melt channel (110), having a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least one melt guiding means (40) is arranged for moving molten material (200) from the center (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for moving molten material (200) from the edge (24) of the melt inlet (20) to the center (32) of the melt outlet (30),
   characterized in that
   the blow head (100) has a displacement device (60), which is designed for the displacement of the overturning device (10) between a first position, in which the melt inlet (20) and the melt outlet (30) are located in fluid-communicating connection with the melt channel (110) and a second position, in which the melt inlet (20) and the melt outlet (30) are separated from the melt channel (110).
2. The blow head (100) according to Claim 1,
   characterized in that
   the at least one melt guiding means (40) has a first guide channel (42) with a guide opening (42a) in the center (22) of the melt inlet (20) and at least one guide outlet (42b) on the edge (34) of the melt outlet (30) and/or the at least one melt guiding means (40) has a second guide channel (44) with a guide outlet (44b) in the center (32) of the melt outlet (30) and at least one guide opening (44a) on the edge (24) of the melt inlet (20).
3. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the at least one melt guiding means (40) has a dividing section (46) with a first sub-channel (46a) and a second sub-channel (46b), wherein a distribution section (47) for distributing the molten material (200) to the sub-channels (46a, 46b) is arranged upstream of the dividing section (46) and a combination section (48) for combining the molten material (200) from the sub-channels (46a, 46b) is arranged downstream of the dividing section (46) and/or the combination section (48) is designed for a central combining of the edge sections of the molten material (200).
4. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the displacement device (60) has a melt channel piece (114) with a length, which corresponds or substantially corresponds to the distance between the melt inlet (20) and the melt outlet (30).
5. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the displacement device (60) has a guide section (62) for guiding the displacement movement between the first position and the second position.
6. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the displacement device (60) is designed for a displacement of the overturning device (10) between the first position and the second position along a translational path, in particular, along a straight line.
7. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the displacement device (60) has a drive device (64), in particular, in the form of an electric motor, for implementing the displacement between the first position and the second position.
8. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the overturning device (10) is arranged with respect to the length of the melt channel (110) in the center or substantially in the center of the melt channel (110).
9. The blow head (100) according to any one of the preceding claims,
   characterized in that
   the displacement device (60) is designed for at least two overturning devices (10), in order to make possible a joint displacement of two overturning devices (10), between a first position, in which the first overturning device (10) is located in fluid-communicating connection with the melt channel (110), and a second position, in which the second overturning device (10) is located in fluid-communicating connection with the melt channel 10).
10. A method for implementing a rinsing process in a blow head (110) with the features of any one of Claims 1 to 9, having the following steps:

    - Displacement of the overturning device (10) by means of the displacement device (60) into a position with fluid-communicating connection with the melt channel (110),

    - introduction of a molten material (200) into the melt inlet (20) of the overturning device (10),

    - moving of molten material (200) from the center (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) of the overturning device (10),

    - moving of molten material (200) from the edge (24) of the melt inlet (20) to the center (32) of the melt outlet (30) and

    - displacement of the overturning device (10) by means of the displacement device (60) into a position without fluid-communicating connection with the melt channel (110).

Images